Galactic synchrotron emissivity measurements between 250° MWA

Su, H.; Hurley-Walker, N.; Jackson, C. A.; McClure-Griffiths, N. M.; Tingay, S. J.; Hindson, L.; Hancock, P.; Wayth, R. B.; Gaensler, B. M.; Staveley-Smith, L.; Morgan, J.; Johnston-Hollitt, M.; Lenc, E.; Bell, M. E.; Callingham, J. R.; Dwarkanath, K. S.; For, B. Q.; Kapińska, A. D.; McKinley, B.; Offringa, A. R.; Procopio, P.; Wu, C.; Zheng, Q.

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Author

Su, H.

Hurley-Walker, N.

Jackson, C. A.

McClure-Griffiths, N. M.

Tingay, S. J.

Hindson, L.

Hancock, P.

Wayth, R. B.

Gaensler, B. M.

Staveley-Smith, L.

Morgan, J.

Johnston-Hollitt, M.

Lenc, E.

Bell, M. E.

Callingham, J. R.

Dwarkanath, K. S.

For, B. Q.

Kapińska, A. D.

McKinley, B.

Offringa, A. R.

Procopio, P.

Wu, C.

Zheng, Q.

Abstract

Synchrotron emission pervades the Galactic plane at low radio frequencies, originating from cosmic ray electrons interacting with the Galactic magnetic field. Using a low-frequency radio telescope, the Murchison Widefield Array (MWA), we measure the free-free absorption of this Galactic synchrotron emission by intervening HII regions along the line of sight. These absorption measurements allow us to calculate the Galactic cosmic-ray electron emissivity behind and in front of 47 detected HII regions in the region $250^\circ